The present invention relates generally to shock absorbers for vehicles or the like, and more specifically to shock absorber assemblies having provisions for vehicle leveling to maintain a predetermined height relationship between the chassis of the vehicle and its ground-engaging wheel and axle assembly.
Various vehicle leveling systems have been included in or with shock absorber components, wherein a pressurized fluid such as pressurized air is admitted or released from a pressurizable fluid chamber in connection with a strut or shock absorber. In prior assemblies of this type, the pressurizable fluid chamber has been used as an air suspension device for assisting a primary or other suspension system, as well as being used as a load-leveling apparatus. In addition, such prior systems have included vehicle height sensing devices adapted to sense sustained changes in the height relationship between the chassis and the ground-engaging wheel and axle assembly in order to cause admission or release of pressurized fluid to or from the pressurizable fluid chamber in order to maintain a desired vehicle height relationship. Some recent examples of such suspension systems, both with and without the height sensing provisions discussed above, include U.S. Pat. Nos. 3,954,257; 4,017,099; 4,067,558; 4,141,572; and 4,206,907, the disclosures of which are all incorporated by reference herein.
Although the above-discussed prior shock absorber and suspension systems have generally provided significant advantages over their predecessors, many of such prior shock absorber or suspension systems have proved to be relatively expensive, complex, or inconvenient to manufacture or service. Furthermore, many of the prior shock absorber and leveling systems have required the replacement of both the shock absorber portion of the system, as well as the vehicle leveling portion of the system, whenever either of these components required replacement.
Therefore, it is a general object of the present invention to provide a new and improved shock absorbing and vehicle leveling system in the form of a shock absorber assembly that is adaptable to either conventional hydraulic shock absorbers or to strut-type shock absorber devices for automotive vehicles and for other applications.
A more specific object of the present invention is to provide a new and improved shock absorbing and vehicle leveling system that allows the shock absorber portion of the system and the vehicle leveling portion of the system to be removable and separately replaceable as independent sub-assemblies.
Still another object of the present invention is to provide a shock absorbing and vehicle leveling system wherein the shock absorber portion of the system and the vehicle portion of the system are separate sub-assemblies that are each interchangeable with other corresponding components having different characteristics such that the characteristics or operating parameters of each of these sub-assemblies can be optimized for a given shock absorber assembly application.
Still another of the basic objectives of the present invention is to provide a new and improved shock absorbing and vehicle leveling system having a relatively simple design, that is economical to manufacture, and which has a long and effective operational life.
In accordance with one aspect of the present invention, a fluid adjustable shock absorber assembly includes a shock absorber component having an elongated shock absorber housing and a piston rod extending from a longitudinally outer end of the housing for longitudinal movement relative thereto, as well as a generally hollow chamber member generally surrounding at least a portion of the shock absorber and sealingly interconnected with an outer end of the shock absorber's piston rod. A flexible diaphragm member is sealingly interconnected with the chamber member and the housing of the shock absorber such that the chamber member and the diaphragm member define a pressurizable fluid chamber with the shock absorber's piston rod and housing. An electrical inductance sensing device is fixedly attached to the chamber member, which is preferably relatively rigid, and is contained substantially wholly therein for sensing the relative longitudinal positions of the shock absorber housing and piston rod. The electrical inductance sensing device can be used either with or without the pressurizable fluid chamber and diaphragm. Preferably, the electrical inductance sensing device is fixedly interconnected with a longitudinally inner end of the chamber member and extends longitudinally outwardly therewithin. A fluid pressure supply system is operable in response to the sensing of the varying relative longitudinal positions of the shock absorber housing relative to the piston rod for supplying a pressurized fluid to, and venting pressurized fluid from, the pressurizable fluid chamber in order to adjust or maintain the relative longitudinal positions of the shock absorber housing and piston rod within predetermined limits. By such adjustments, the shock absorber assembly maintains the vehicle height relative to its ground-engaging axle and wheel assembly within predetermined desirable limits.
In accordance with another aspect of the present invention, which can be employed either with or without the above-mentioned features of the present invention, a diaphragm support member is provided for laterally supporting at least a portion of the flexible diaphragm member in a laterally spaced-apart relationship with the shock absorber housing at least at a pair of longitudinally spaced-apart positions on the shock absorber housing. Preferably, the diaphragm support member, which is sealingly interconnected with the flexible diaphragm member, is removably and sealingly interconnected with the shock absorber housing, and the diaphragm member is sealingly and removably interconnected with the piston rod, such that the diaphragm support member and the diaphragm member (as well as a relatively rigid chamber member, if any) are removable as a separate sub-assembly from the shock absorber itself.
In accordance with still another aspect of the present invention, which can also be employed with or without the various features mentioned above, the pressurizable fluid chamber includes a longitudinally fixed portion of the chamber member or other enclosure in part forming the fluid chamber, a flexible diaphragm member, and a sensor support member for the above-mentioned electrical inductance sensing device. The sensor support member and the sensing device generally surround the shock absorber and are spaced laterally outwardly therefrom. The sensor support member includes a laterally outwardly-extending flange thereon, and the longitudinally fixed portion of the fluid chamber enclosure is forcibly and permanently deformed in a generally laterally inward direction on opposite longitudinal sides of the support member flange portion in order to fixedly secure the sensor support member to enclosure. Preferably, a ring, which can be a one-piece structure or a composite structure, and which can be resilient or relatively rigid, is disposed on at least one longitudinal side of the support member flange portion in order to retain the sensing device components and/or to resiliently protect the sensor support member and the sensor device itself as the longitudinally fixed portion of the fluid chamber enclosure is forcibly deformed laterally inwardly.
Additional objects, advantages, and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.